[PCB_FORUM] Re: AW: positive dynamic gnd/pwr planes in 15.2
- From: "Gary MacIndoe" <gary.macindoe@xxxxxxx>
- To: icu-pcb-forum@xxxxxxxxxxxxx
- Date: Wed, 4 May 2005 09:05:56 -0600
Hello Johannes,
My database is in mils, with an accuracy of 1 (1 decimal point, which
equates to 1/10,000 of an inch!). There is no point in having a greater
accuracy, the fab houses can't do it.
So I can't try 0.01 or 0.02, but when I try 0.4, most of the DRCs went away,
leaving me with only 3 (they are all actual 7.9 for constraint of 8).
Anyhow, this is ridiculous! I shouldn't have to "play games" to get the
shape to fill correctly. Cadence needs to fix this, once and for all.
I've been using Allegro since version 5.x (I believe it was 1995). I had to
play the games with positive planes back then, and still now, eleven years
later! I got tired of the games, went to negative planes about six years
ago and have never looked back. Guess I'll stick with them.
Thanks for your response!
Gary E. MacIndoe
PCB Design Engineer
Advanced Micro Devices, Inc.
Longmont, Colorado
-----Original Message-----
From: icu-pcb-forum-bounce@xxxxxxxxxxxxx
[mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx]On Behalf Of
Johannes.Schlenger@xxxxxxxxxxxxxxxxxxx
Sent: Wednesday, May 04, 2005 6:31 AM
To: icu-pcb-forum@xxxxxxxxxxxxx
Subject: [PCB_FORUM] AW: positive dynamic gnd/pwr planes in 15.2
Hey Gary,
put in at 'Global Dynamic Shape Parametsr' under Clearances in the field
'Oversize value' the value 0.01 mil or 0.02 mil,
this will solve your problem with the DRCs.
Johannes Schlenger
PCB Designer
Fujitsu-Siemens-Computers
----------------------------------------------------------------------------
--
Von: icu-pcb-forum-bounce@xxxxxxxxxxxxx
[mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx] Im Auftrag von Gary MacIndoe
Gesendet: Dienstag, 3. Mai 2005 23:56
An: Allegro Forum
Betreff: [PCB_FORUM] positive dynamic gnd/pwr planes in 15.2
Hey Guys,
Those of you that create your gnd/pwr inner planes as positive and
dynamic, do you have problems after creating them? I always create mine as
negative, but I'm playing around with positives with the new fangled dynamic
shapes.
After the shape is created (either with Edit -> Split Plane -> Create, or
with Shape -> Polygon/Rectangle), there are a number of DRCs (not allot,
maybe 9 or so on a 7" square board). These DRCs are via-to-shape, and have
an actual value of 9.9 for a constraint value of 10, and some were 4.6
actual for a 5 constraint.
Are you positive plane people seeing this also? Is there a way to avoid
this? I managed to get some of them to go away by giving a Global Dynamic
Shape Parameter, Via Oversize value of 1 (I went to "2", and the DRC count
was the same, I went to "3" and my DRC count increased by one!).
This is reminding me of the "not so good old days" of "problem points"!
Thanks for any responses!
Gary E. MacIndoe
PCB Design Engineer
Advanced Micro Devices, Inc.
Longmont, Colorado
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